diff --git a/apecs.cabal b/apecs.cabal
--- a/apecs.cabal
+++ b/apecs.cabal
@@ -1,5 +1,5 @@
 name:                apecs
-version:             0.4.0.0
+version:             0.4.0.1
 homepage:            https://github.com/jonascarpay/apecs#readme
 license:             BSD3
 license-file:        LICENSE
diff --git a/src/Apecs/Util.hs b/src/Apecs/Util.hs
--- a/src/Apecs/Util.hs
+++ b/src/Apecs/Util.hs
@@ -25,6 +25,7 @@
 import           Control.Applicative  (liftA2)
 import           Control.Monad.Reader (liftIO)
 import           Data.Monoid
+import           Data.Semigroup
 import           Data.Proxy
 import           System.CPUTime
 import           System.Mem           (performMajorGC)
@@ -39,7 +40,7 @@
 
 -- | Component used by newEntity to track the number of issued entities.
 --   Automatically added to any world created with @makeWorld@
-newtype EntityCounter = EntityCounter {getCounter :: Sum Int} deriving (Monoid, Eq, Show)
+newtype EntityCounter = EntityCounter {getCounter :: Sum Int} deriving (Semigroup, Monoid, Eq, Show)
 
 instance Component EntityCounter where
   type Storage EntityCounter = Global EntityCounter